The overall function of the Vector Core is to provide high quality retroviral vectors and adeno-associated virus (AAV) vectors to investigatOrs of this SCOR grant. Virtually all of the projects in this SCOR proposal involve utilizing retroviral vectors as an experimental tool to introduce specific genes into hematopoietic stem cells or into different hematopoietic cell lines. The Vector Core will provide different backbone vectors and packaging cell lines as well as appropriate technical advice relating to the most efficient way to engineer high titer vectors for these different studies. The Vector Core will also provide large quantities of retroviral vectors for the baboon studies in Project 6 and will assure that these different vectors are of similar titer. For the human studies proposed in Project 7 the Vector Core will assure production of clinical grade retroviral vectors for use in the gene therapy of leukocyte adherence deficiency (LAD). Quality control assays meeting FDA and RAC requirements including assays for replication-competent virus, adventitious infectious agents, and retroviral genomic rearrangements will largely be carried out in the Vector Core facility or contracted through Microbiological Associates.